1 J Nutr Food Sci, Vol. 11 Iss. 8 No: 811 OPEN ACCESS Freely available online Research Article Correspondence to: Krishnakumar Illathu Madhavamenon, Chief Research Officer, R and D Centre, Akay Natural Ingredients Ltd, Cochin, Kerala, India, Tel: +91-4842686111, Fax: +91-4842680891; Email: krishnakumar.im@akay-group.com Received: June 14, 2021; Accepted: June 28, 2021; Published: July 05, 2021 Copyright: © 2021 Ramalingam K, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Kannan Ramalingam 1 , Ramadasan Kuttan 2 , Syam Das Sivadasan 3 , Sibi Ittiyavirah 1 and Krishnakumar Illathu Madhavamenon 3* 1 Department of Pharmaceutical Sciences, Mahatma Gandhi University, Kerala, India; 2 Amala Cancer Research Centre, Thrissur, Kerala, India; 3 Chief Research Officer, R and D Centre, Akay Natural Ingredients, Cochin, Kerala, India ABSTRACT Background: Despite the increasing usage of black cumin (Nigella sativa) oil (BCO) in Dietary supplements/ Nutraceuticals, systematic investigations on the role of its major bioactive component, thymoquinone (TQ) on its safety aspects have not been reported. Method: Herein, we investigated the safety of BCO containing 0.6 and 5% (w/w) of TQ (BCO-0.6 and BCO-5) by single-dose acute and subchronic (90-day) repeated dose toxicity studies in Wistar rats, as per OECD guidelines. Results: While BCO-0.6 was safe at 300 - 2000 mg/kg b. wt. upon single-dose (90-day) study at 0.1, 0.05 and 0.01 mL/kg b.wt. (94, 47, 9.4 mg/kg b.wt) of BCO-5 (i.e., at 5, 2.5 and 1 mg/kg b. wt. of TQ) established its no-observed-adverse-effect-level (NOAEL) as 0.1 mL/kg or 94 mg/kg b. wt. (5 mg of TQ/kg b. wt.). Conclusion: Black cumin oil containing 5% (w/w) of TQ content was found to have a NOAEL of 0.1 mL/ kg or 94 mg/kg b. wt. in rodents; which also corresponds to a dose of 5 mg of TQ/kg b. wt. From this study, the safe human dosage may be derived as not more than 900 mg/kg b. wt. of BCO-5/day or 50 mg of TQ/adult/day. Keywords: Black seed; Black cumin oil; Dietary supplement; Nigella Sativa; Nutraceutical; Repeated-dose; Safety; Thymoquinone; Toxicity INTRODUCTION Nigella sativa, commonly known as ‘black cumin’ or ‘black seed’ has received a recent interest owing to its health beneficial pharmacological activities as evident from the preclinical and clinical studies. In the field of Nutraceuticals, black cumin oil (BCO) is emerging as a miracle herbal agent for health and wellness. According to the American Botanical Council's herbal supplement market research, the sales of black cumin containing products in the USA increased by 200% in 2017 [1]. Black cumin is mainly growing in the Mediterranean region, Middle East, India and Pakistan [2,3]. The plant is mainly cultivated for its seed, and is an approved food flavouring agent and kitchen spice in USA and Europe (FDA 182.20; EFSA 8014-13-9). Seeds and oil of black cumin have been established to possess medicinal effects [2-5]. In the traditional systems of medicine such as Ayurveda and Unani, it is widely using in the treatment of various diseases [5]. Black cumin is known as the 'seed of blessings'. In the Arab systems of medicine, it is also regarded as a ‘cure’ for all forms of diseases [2-5]. Black cumin and its oil have been extensively researched for their therapeutic potential and has been shown to possess broad range of pharmacological activities, including antioxidant, anti- inflammatory, antimicrobial, hepatoprotective, anticancer, immunomodulatory, diuretic, antihypertensive, antidiabetic, anthelmintic, gastroprotective, analgesic, spasmolytic, bronchodilator and skin protective effects [6]. Several studies on black cumin and its oil have suggested that the biological activity of BCO could be specifically due to the essential oil components, particularly the thymoquinone (TQ). Several other active compounds, including p-cymene (7-15%), carvacrol (6-12%), 4-terpineol (2-7%), t-anethole (1-4%) and longifene (1-8%) have also been identified as volatile constituents of BCO in addition to the fatty acids such as linoleic acid, oleic acid, palmitic acid and linolenic acid [7]. Several clinical trials of black cumin oil at different dosage ranging from 1 to 12 mL/day have been reported [8]. While most of these studies have not provided an estimate of TQ levels in the oil used in the studies, it has been found that higher oil doses (5 to 10 mL/day) is generally required to provide significant health benefits, suggesting the need for a higher dose of TQ per day. Thus, black cumin oil with higher levels of TQ has recently been widely using as Dietary supplements and Nutraceuticals. However, most of the currently available supplements do not have standardised TQ levels on the label. Furthermore, no systematic studies have been performed on the role TQ content on the safety of these oils. Al- Journal of Nutrition & Food Sciences Safety Assessment of a Thymoquinone-rich Black Cumin Oil (BlaQmax ® ): Acute and Sub-chronic Toxicity Studies oral acute toxicity study, LD 50 cut off dose for BCO-5 was in the range >50-300 mg/kg b. wt. Further repeated-dose Ali et al. have reported the oral LD 50 of synthetic thymoquinone Citation: Ramalingam K, Kuttan R, Sivadasan SD, Ittiyavirah S, Madhavamenon KI (2021) Safety Assessment of a Thymoquinone rich Black Cumin Oil (BlaQmax ® ): Acute and Sub chronic Toxicity Studies. J Nutr Food Sci. 11:811.